Assessment of the health status of wild fish from the wheatley Harbour area of Concern, Ontario, Canada

Abstract

The overall health and endocrine function of wild brown bullhead (Ameiurus nebulosus) and goldfish (Carassius auratus) from the Wheatley Harbour Area of Concern (Lake Erie, Ontario, Canada) was assessed using a suite of physiological and biochemical endpoints. Smaller gonads were detected in female brown bullhead and goldfish from Wheatley Harbour compared with Hillman Marsh (Ontario, Canada) reference fish. Female brown bullhead exhibited decreased in vitro synthesis of 17β-estradiol. Female goldfish had decreased plasma vitellogenin concentrations. Plasma testosterone and 11-ketotestosterone were significantly depressed in males of both species. Perturbations in the thyroid status were detected, but varied between sexes and species. Observed differences included lower plasma concentrations of thyroid hormones and/or elevated liver deiodinase activity. Histological evaluation of the thyroid tissue indicated that in the case of female goldfish, those perturbations stimulated the thyroid (as indicated by increased thyroid epithelial cell height) and partially depleted the thyroxine reserves, as indicated by decreased colloid and elevated thyroid activation index. Increased mixed-function oxygenase activity in brown bullhead from Wheatley Harbour was consistent with exposure to planar aromatic contaminants. A principal component analysis of selected variables showed the separation of fish by collection site. The endpoints most strongly associated with the separation were generally those exhibiting significant differences between sites. The results of the present study indicate that the health of fish populations within Wheatley Harbour warrants continued attention.

Halogenated phenolic compounds in wild fish from Canadian Areas of Concern

“…Two of the health studies on wild fish from the Canadian Great Lakes AOCs reported significant endocrine effects in fish from exposed sites, in comparison with those from reference sites, consistent with the presence of halogenated phenolic compounds reported in the present study [23,24]. Plasma from Figure 5.…”

“…Thus, we have associations between contaminants and hormones, both steroidal and thyroidal, in plasma from the same fish sets. Gilroy et al [23] reported decreased thyroxine concentrations and increased thyroid epithelial cell height in female goldfish from Muddy Creek (Wheatley Harbour AOC), compared with those from the reference site, Hillman Marsh, consistent with a thyroxine depletion common in animals that have been exposed to halogenated phenolic compounds [43]. Simmons et al [24] reported, notably, greater body concentrations of coplanar PCBs and dioxins in fish from Belleville and Trenton (Bay of Quinte AOC) compared with the reference site (Deseronto).…”

“…Triclosan has been reported in wastewater, surface water, and aquatic biota [12,[19][20][21][22]. Environment Canada has conducted studies to address the health status of wild fish populations from several Canadian Great Lakes AOCs, to monitor their general health, as well as indicators of endocrine disruption [23,24], and to measure plasma concentrations of halogenated phenolic compounds as a real-time indicator of environmental exposure [5,6] to relate observed health effects to concentrations of environmental contaminants.…”

Deiodinases and thyroid metabolism disruption in teleost fish

“…Authors hypothesized that, because of structural similarities, PCBs were able to displace THs from serum binding proteins, causing a decrease in serum levels by biliary clearance. This may explain the correlation found between T3/T4 ratio and PCBs in fish from San Francisco Bay and the Great Lakes (Brar et al, 2010;Gilroy et al, 2012). Ultimately, increases in T4ORD activity, together with parallel decreases in sulfotranferases, enzymes that inactivate and promote TH excretion, would compensate and restore T3 concentration.…”

Polychlorinated biphenyls and their hydroxylated metabolites in wild fish from wheatley Harbour Area of Concern, Ontario, Canada

“…Briefly, brown bullhead (298 AE 135.3 g, 4 AE 1.3 years old [mean AE standard deviation], n ¼ 42 selected for this particular study) were collected using overnight hoop nets between September 11 and 18 (Wheatley Harbour and Hillman Marsh) and between October 1 and 9 (Turkey Creek), 2002. Fish were sacrificed by a blow to the head, the various samples and organs were collected and stored as required [25], and the remaining carcasses were kept on dry ice until return to the laboratory, where they were frozen at À208C until analysis. Fish were anesthetized in a clove oil bath ($0.05 þ $0.025% ethanol to aid emulsification).…”